Interesting. Glad I saw this before my next game, I'll try it out.
Even though I have done considerable testing with the QB auto sub (even at extremes) I'm all but certain the QB will never, ever sub out (he will likey just stumble around and then fumble if someone sneezes too loud).
I also don't mind the OL subs, because they are annoyingly immune to injury and it makes OL depth somewhat important. But I am interested in the dynamic effect it may have in line play in general. Are you making these changes as a whole, or just in CFM?